Peripheral NMDA Receptors in Visceral Nociception

内脏伤害感受中的外周 NMDA 受体

• 批准号: 7288788
• 负责人: JAMES A MCROBERTS
• 金额: $ 27.68万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7288788
• 关键词: Accounting; Address; Afferent Neurons; Afferent Pathways; CALCA gene; Calcitonin; Calcitonin Gene-Related Peptide; Calcium; Colitis; Colon; Coupling; D Aspartate; Development; Disease; Electrophysiology (science); Event; Funding; Genes; Genus Cola; Glutamate Receptor; Goals; Grant; Hyperalgesia; In Vitro; Inflammation; Inflammatory; Intestines; Knock-out; Knockout Mice; Lead; Mechanics; Mediating; Molecular; Molecular Biology Techniques; Mus; N-Methyl-D-Aspartate Receptors; NR1 gene; Nature; Neurons; Neuropeptides; Nociception; Pain; Pathway interactions; Perception; Peripheral; Peripheral Nerves; Phosphorylation; Play; Process; Property; Protein Kinase; Protein Kinase C; Range; Receptor Activation; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Research Personnel; Resistance; Role; S100A12 gene; Signal Transduction; Signal Transduction Pathway; Spinal Ganglia; Spinal cord posterior horn; Stimulus; Substance P; TRPV1 gene; Tetrodotoxin; Tissues; Up-Regulation; Validation; Visceral; Visceral Afferents; Visceral pain; afferent nerve; allodynia; aspartate receptor; central sensitization; citrate carrier; colon distension; dorsal horn; human NR1 protein; human S100A12 protein; ifenprodil; in vivo; neuronal excitability; postsynaptic; presynaptic; receptor; receptor coupling; research study; src-Family Kinases; transmission process; voltage

DESCRIPTION (provided by applicant): Functional and inflammatory disorders of the gut are characterized by allodynia (the perception of a normally non-painful stimulus as painful) and hyperalgesia (the enhanced perception of pain). The development of visceral hyperalgesia and its underlying central sensitization relies crucially on the activation of a particular type of glutamate receptor, the NMDA receptor (NMDAR), located on postsynaptic neurons in the dorsal horn of the spinal cord. Recently, a presynaptic NMDAR on the central terminals of extrinsic primary afferent neurons (EPANs) has been shown to regulate the release of substance P into the superficial dorsal horn, thereby contributing to central sensitization. It is likely that NMDAR subunits synthesized in DRG neurons of EPANs innervating the colon are transported not only to central, but also to peripheral nerve terminals. During the initial funding period of this grant, we have identified the NMDAR subunits expressed by EPANs and evaluated their functional properties. We found that activation of NMDARs in the colon acts to sensitize certain afferent terminals to mechanical distension. Using DRG neurons in primary culture, we showed that NMDAR activation enhances voltage gated calcium currents through a process that involves protein kinase C. Whether this mechanism accounts for the enhanced sensitivity of peripheral afferent nerve terminals to mechanical stimuli, and the nature of the intracellular transduction events coupling NMDAR to protein kinase C (PKC) and other downstream targets will be addressed in the renewal application. In addition, we showed that colon inflammation results in enhanced NMDAR signaling in DRG neurons, which is associated with phosphorylation of one of the NMDAR subunits. In this competitive renewal application, using a combination of in vivo (validated, targeted KO mice) and in vitro techniques (molecular biology, electrophysiology), we propose new experiments to address the following 3 hypotheses: 1) NMDARs on EPANs innervating the colon play a role in peripheral sensitization by regulating neuronal excitability and neuropeptide release. 2) Sensitization of EPAN terminals is mediated by the NMDAR through PKCepsilon and PKD activation. 3) Colon inflammation sensitizes DRG neurons via phosphorylation of NMDARs by non-receptor tyrosine kinases. These studies are likely to contribute significantly to our understanding of the mechanisms underlying enhanced visceral pain associated with functional and inflammatory disorders of the Gl tract.

描述（由申请人提供）：肠道的功能性和炎症性疾病的特征是异常性（正常无pain的刺激视为疼痛）和痛觉过敏（对疼痛的感知增强）。内脏性痛觉过敏及其潜在的中央敏化的发展依赖于特定类型的谷氨酸受体NMDA受体（NMDAR）的激活，该受体位于脊髓的背角中的突触后神经元上。最近，已证明外部原发性传入神经元（EPAN）中央末端的突触前NMDAR可调节物质p释放到浅表背角中，从而有助于中央敏化。在结肠支配的Epan的DRG神经元中合成的NMDAR亚基不仅被运输到中心，还传输到周围神经末端。在本赠款的最初资助期间，我们已经确定了EPAN表达的NMDAR亚基并评估了其功能特性。我们发现结肠中NMDAR的激活作用于将某些传入终端敏感到机械扩张。 Using DRG neurons in primary culture, we showed that NMDAR activation enhances voltage gated calcium currents through a process that involves protein kinase C. Whether this mechanism accounts for the enhanced sensitivity of peripheral afferent nerve terminals to mechanical stimuli, and the nature of the intracellular transduction events coupling NMDAR to protein kinase C (PKC) and other downstream targets will be addressed在续订申请中。此外，我们表明结肠炎症会导致DRG神经元中NMDAR信号的增强，这与NMDAR亚基之一的磷酸化有关。 In this competitive renewal application, using a combination of in vivo (validated, targeted KO mice) and in vitro techniques (molecular biology, electrophysiology), we propose new experiments to address the following 3 hypotheses: 1) NMDARs on EPANs innervating the colon play a role in peripheral sensitization by regulating neuronal excitability and neuropeptide release. 2）EPAN末端的敏化是由NMDAR通过PKCEPSILON和PKD激活介导的。 3）结肠炎症通过非受体酪氨酸激酶通过NMDAR的磷酸化来使DRG神经元敏感。这些研究可能会为我们理解与GL道的功能和炎症性疾病相关的内脏疼痛增强的机制做出重大贡献。